Total parenteral nutrition (TPN) has been linked to conditions that promote intestinal atrophy, mucosal dysfunction and protein malnutrition. Parenterally-fed subjects also exhibit exaggerated hormone and cytokine response to endotoxin. Since addition of glutamine to parenteral formula has prevented loss of intestinal morphology in animal models and to conserve skeletal muscle protein this study will test whether supplementation of TPN with glutamine may work similarly in humans.